Relationships between residual feed intake, average daily gain, and feeding behavior in growing dairy heifers

Abstract

Residual feed intake (RFI) is a measure of an individual's efficiency in utilizing feed for maintenance and production during growth or lactation, and is defined as the difference between the actual and predicted feed intake of that individual. The objective of this study was to relate RFI to feeding behavior and to identify behavioral differences between animals with divergent RFI. The intakes and body weight (BW) of 1,049 growing dairy heifers (aged 5-9 mo; 195 ± 25.8 kg of BW) in 5 cohorts were measured for 42 to 49 d to ascertain individual RFI. Animals were housed in an outdoor feeding facility comprising 28 pens, each with 8 animals and 1 feeder per pen, and were fed a dried, cubed alfalfa diet. This forage diet was chosen because most dairy cows in New Zealand are grazed on ryegrass-dominant pastures, without grain or concentrates. An electronic feed monitoring system measured the intake and feeding behavior of individuals. Feeding behavior was summarized as daily intake, daily feeding duration, meal frequency, feeding rate, meal size, meal duration, and temporal feeding patterns. The RFI was moderately to strongly correlated with intake in all cohorts (r=0.54-0.74), indicating that efficient animals ate less than inefficient animals, but relationships with feeding behavior traits (meal frequency, feeding duration, and feeding rate) were weak (r=0.14-0.26), indicating that feeding behavior cannot reliably predict RFI in growing dairy heifers. Comparison of the extremes of RFI (10% most and 10% least efficient) demonstrated similar BW and average daily gain for both groups, but efficient animals ate less; had fewer, longer meals; shorter daily feeding duration; and ate more slowly than the least-efficient animals. These groups also differed in their feeding patterns over 24h, with the most efficient animals eating less and having fewer meals during daylight (0600 to 2100 h), especially during the afternoon (1200 to 1800 h), but ate for a longer time during the night (0000-0600 h) than the least-efficient animals. In summary, correlations between RFI and feeding behavior were weak. Small differences in feeding behavior were observed between the most- and least-efficient animals but adverse behavioral effects associated with such selection in growing dairy heifers are unlikely.

Residual feed intake is repeatable for lactating Holstein dairy cows fed high and low starch diets

“…These results are similar to other reports for beef and dairy animals (Castro Bulle et al, 2007;Kelly et al, 2010b;Green et al, 2013). Consistent with these results, the most feed efficient cows (n = 11) ate ~5 kg of DM/d less than the least efficient cows in our study.…”

“…An animal with a negative RFI consumes less than expected for its level of production and thus is more efficient when RFI is used to define feed efficiency. Because RFI is independent of production level, recent attention has been given to using RFI as a tool to assess feed efficiency in dairy cattle for purposes of genetic selection (Connor et al, 2013;Green et al, 2013;Macdonald et al, 2014). The heritability of RFI is 0.15 to 0.19 in lactating dairy cattle (van Arendonk et al, 1991;Tempelman et al, 2015) and 0.22 to 0.38 in growing dairy heifers (Williams et al, 2011;Pryce et al, 2012).…”

Feeding behavior, ruminal fermentation, and performance of pregnant beef cows differing in phenotypic residual feed intake offered grass silage1

“…Similar to feeding systems used in other studies (e.g., Dobos and Herd, 2008;Williams et al, 2011;Green et al, 2013), a limitation of the system used in the current experiment is that it is unable to distinguish between actual ingestion of feed, or head-down duration, and instances where the animal's head is at the feed bin and not consuming any feed. This may lead to the overestimation of actual feeding time or feeding events by the animal, and caution must be exercised when comparing studies with different definitions of feeding or feeding events.…”

“…In contrast, in studies using, for example, the GrowSafe automated feed intake measurement system (e.g., Basarab et al, 2011;Durunna et al, 2011Durunna et al, , 2012, a distinction between head-down duration and total feeding duration could be made, with the head-down duration enabling the investigation of intensity of feeding activities at the feed bin (Durunna et al, 2011). Nevertheless, it is evident from the literature that most studies examining differences in total feeding duration have reported a shorter daily time in low-RFI compared to high-RFI animals whether using the GrowSafe feeding system (Nkrumah et al, 2006(Nkrumah et al, , 2007Lancaster et al, 2009;Durunna et al, 2011Durunna et al, , 2012Hafla et al, 2013;Kayser and Hill, 2013) or other automated feed intake systems (Dobos and Herd, 2008;Green et al, 2013), which is in accord with the findings of the current study using the Griffith Elder system. In contrast, Basarab et al (2011), using the GrowSafe system, Kelly et al (2010a), using the Insentec feeding system, and Williams et al (2011), using an automated feed intake unit, reported no differences in total feeding duration between heifers of high and low RFI offered whole-crop silage plus concentrates and alfalfa hay cubes, respectively.…”

Short communication: Grazing pattern of dairy cows that were selected for divergent residual feed intake as calves

“…This interest has led to the evaluation and characterization of RFI in calves during growth and in cows during lactation ). An analysis of calf feeding behavior during selection for RFI has been undertaken (Green et al, 2013), and gene expression and heritability has been demonstrated in New Zealand dairy cattle . Animals vary in their behavior and efficiency for production, but measurement of RFI and identification of divergence must be conducted under confined feeding environments.…”